Anthony Ferrante coordinated the U.S. government’s response to Russian election interference. Now he’s helping a news site defend itself from a Russian billionaire’s lawsuit.

The logo of news website BuzzFeed is seen on a computer screen in Washington on March 25, 2014. (Nicholas Kamm/AFP/Getty Images)

For the last six months, a team led by a former top FBI and White House cybersecurity official has been traveling the globe on a secret mission to verify parts of the Trump dossier, according to four sources familiar with different aspects of the ongoing probe.

Their client: BuzzFeed, the news organization that first published the dossier on U.S. President Donald Trump’s alleged ties to Russia, which is now being sued over its explosive allegations.

The investigation, being conducted by FTI Consulting, is running in parallel to special counsel Robert Mueller’s probe into possible collusion between the Trump campaign and Russia in Kremlin-directed efforts to interfere with the 2016 presidential election. With the special counsel probe under wraps, the BuzzFeed court case could represent the first public airing of an investigation into the veracity of some of the dossier’s claims.

FTI is a Washington-based business advisory firm that specializes in areas ranging from corporate litigation to forensic accounting, and it is a frequent post-government landing pad for FBI officials.

The ramifications of FTI’s dossier investigation could be game-changing for Mueller’s probe, because it “would establish outside veracity of dossier allegations,” a source familiar with the work told Foreign Policy. Yet news of FTI’s involvement, including the critical role of a former top FBI official, would also be controversial because the dossier itself is “a political football,” the source said.

The dossier, which was funded by those connected with the Hillary Clinton campaign and the Democratic Party, has been the subject of ongoing controversy; while some of its claims have allegedly been verified, many others remain unproven. Trump and his allies have repeatedly attacked those involved in the dossier, as well as top FBI officials, as being involved in a partisan witch hunt.

Ferrante, a former top FBI official who previously served as director for cyber incident response at the U.S. National Security Council during the Barack Obama administration, is now at FTI Consulting, where he is leading the effort.

Ferrante joined the FBI as a special agent in 2005, and he was assigned to the bureau’s New York field office, where he worked on cyber threats to national security. In 2006, he was selected as a member of the FBI’s Cyber Action Team, a group of experts who deploy globally to respond to critical cyber incidents.

As a top FBI cybersecurity official tasked to the White House, Ferrante was in charge of coordinating the U.S. government response to Russian attempts to meddle in the 2016 presidential election, among other responsibilities. Prior to joining the NSC in 2015, Ferrante was chief of staff for the FBI’s cyber division at headquarters under then-Director James Comey. Ferrante, still working for the FBI but at the White House, stayed in his position as director for cyber incident response at the NSC through the Trump administration, until April 2017, when he left to join FTI.

At FTI, Ferrante launched what’s now been a months-long stealth effort chasing down documents and conducting interviews on the ground in various countries around the world. His team directed BuzzFeed lawyers to subpoena specific data and testimony from dozens of agencies or companies across the country and assembled a cyber ops war room to analyze that data, according to sources familiar with the work.

BuzzFeed is being sued for libel by Russian technology executive Aleksej Gubarev, who argues that the news organization was reckless in publishing a series of memos written by former British spy Christopher Steele. Those memos — part of a so-called dossier of information about Trump — include unverified claims that servers belonging to a company owned by Gubarev were used to hack the Democratic Party’s computer systems during the 2016 campaign.

BuzzFeed’s outside attorneys initially hired FTI to verify aspects of the dossier specifically pertaining to the Gubarev lawsuit, but its scope has since expanded. “If it’s fact, it’s not libel, that’s the idea,” one source told FP.

Evan Fray-Witzer, a lawyer for Gubarev, who has strongly denied those claims, mocked BuzzFeed’s efforts.

“They can hire Nancy Drew, Encyclopedia Brown, or Sherlock Holmes – you can’t find what doesn’t exist,” Fray-Witzer wrote to FP. “There is a simple reason why Buzzfeed hasn’t found any evidence to support the allegations in the Dossier against Mr. Gubarev: the allegations are false.”

BuzzFeed’s legal woes don’t end with the Gubarev lawsuit. In January, Trump’s personal lawyer Michael Cohen, who is also mentioned in the dossier, sued BuzzFeed in connection with their publication of the document.

It’s unclear if anyone from FTI will provide testimony before the Florida court presiding over a libel lawsuit against the media outlet. The names of testifying expert witnesses are expected to be disclosed later this week, and there is a hearing currently scheduled for Thursday in Washington, D.C.